Not applicable.
Not applicable.
1. Field of Invention
This invention relates to chuck keys, specifically to such keys used to operate the jaws of a chuck that is normally associated with a hand held electrically driven drill
2. Description of Prior Art
In order to accommodate various rotary tools that may be inserted within the jaws of a chuck in a hand held electrically driven drill means are provided to adjust the opening defined by the jaws. The chuck is ordinarily adjusted by means of a chuck key that normally has a spindle with an associated circular bevel gear. The spindle of the key is engaged into one of a series of radial sockets in the body of the chuck and the key rotated by means of a handle, with the bevel gear on the key engaged to a circular rack gear of the chuck. Rotation of the key opens or closes the jaws of the chuck and thereby facilitates changing the tool clamped in the jaws. Commonly, means are provided on the drill or its power cord to house or suspend the key for ready access.
Various shapes of chuck keys are proposed in the prior art, though the spindle and pinion gear elements have remained basically the same. U.S. Pat. No. 224,119 to Whiton (1880) discloses a xe2x80x9cTxe2x80x9d shaped chuck key and U.S. Pat. No. 2,552,694 to Stoner (1951) shows a modified xe2x80x9cTxe2x80x9d shaped key. U.S. Pat. No. 4,534,573 to Somers (1985) and U.S. Pat. No. 4,652,001 to Rathbun (1987) show xe2x80x9cLxe2x80x9d shaped keys. U.S. Pat. No. 4,133,543 to Johnson (1979) and U.S. Pat. No. 4,467,677 to Grifford (1984) disclose triangle and cross-shaped chuck keys respectively. Although operably adequate and inexpensive to manufacture, these chuck keys have several shortcomings.
Typically, chuck keys have the undesirable tendency to snag. This problem is especially prevalent with chuck keys attached, often by means of a tether, to a drill""s power cord. Snagging occurs when the lips, edges, or angles that define these chuck keys catch on surrounding work site obstructions. A chuck key trolled from a length of power cord will tend to hook adjacent objects much the way a hook on a fishing line will snag the things in its path. There is a possibility of a snag each time a drill is picked up or moved.
An unexpected snag such as this can be hazardous. A drill can be pulled from an operator""s hand or the operator can be thrown off balance. This can be particularly dangerous to an operator working from a ladder or scaffold. Recent statistics show that falls are the leading cause of death in the construction industryxe2x80x94the three leading fatal falls from higher levels being from roofs, scaffolding, and ladders as revealed by Bureau of Labor Statistics, US Dept. of Labor, in cooperation with State and Federal Agencies, Census of Fatal Occupational Injuries, 1994; and xe2x80x9cIssuesxe2x80x9d, Labor Statistics, Summary 96-1 January 1996, a publication of the US Dept. of Labor, Bureau of Labor Statistics. In this situation, individuals below the operator are also put at risk. These work persons or pedestrians can be injured from a falling drill that has been pulled from the hand of an operator. Loose tools and materials can be snagged and pulled over the edge of a working platform, similarly risking injury to those below. Open containers of paint or other liquid can also be snagged and tipped over. Furthermore, these falling or otherwise disturbed objects can damage nearby materials or personal property.
Chuck key snag-related mishaps take their toll economically and emotionally. The cost of repairing or replacing items damaged due to snags can be considerable. Financial compensation for snag-related injury can also be overwhelmingly expensive. Falls and falling objects are two of the three leading causes of workplace injuries, accounting for 86% of the $38.7 billion in direct workers-compensation costs paid in 1998 as revealed by Liberty Mutual Workplace Safety Index. Heightened anxiety over the anticipation of these occurrences and the potential liabilities involved can be unnerving and distract the operator from the work at hand. Efficiency is reduced and frustration is increased with repeated chuck key snags, thus hampering productivity.
Additionally, repeated snagging forces the tether down the power cord, eventually leaving the chuck key out of convenient reach of the operator. Moreover, this action also causes premature wear and failure of the tether.
Typically, chuck keys are rotated with the fingers and thumb to clench a chuck""s jaws about the shaft of a rotary tool. The chuck""s grip on the tool must be strong for effective operation. Operators with limited digital strength are hindered in achieving a sufficient grip on the tool. If the operator experiences soreness or fatigue in one or more of the fingers, or if the hand is cold or gloved, manipulating the key effectively becomes even more difficult. Should a rotary tool subsequently become loose in a chuck while in use, the tool and/or the chuck can be damaged. Therefore, chuck manufacturers recommend the time-consuming procedure of using the key in each of the chuck""s sockets to insure a firm hold on the tool. Loosening the chuck after this can be arduous. Considerable time is lost in the opening and closing of the chuck when the work at hand requires the use of multiple chuck mounted tools.
There are still other undesirable qualities of typical chuck keys. Operators who opt to keep the chuck key off the power cord and in a tool pouch, often discover the key has become lost amongst other articles at the bottom of the pouch. Also, while using the key, it is necessary for the operator""s fingers to move precariously close to the exposed moving gears of the key and chuck.
In accordance with the present invention, a drill chuck key comprises a smooth elongated cylindrical handle having a curved, geared end and an elastomeric tethered chuck key holder.
Accordingly, several objects and advantages of the present invention are:
(a) to provide a chuck key that, when tethered to a drill""s power cord, allows for snag resistant movement about a work site;
(b) to provide a chuck key that, when tethered to a drill""s power cord that must often be pulled, resists the tendency to disturb tools and other materials or to pull them off the edge of working platforms;
(c) to provide a chuck key that will minimize the possibility of snag related injury;
(d) to provide a chuck key that will minimize the possibility of snag related property damage;
(e) to provide a chuck key that allows for increased productivity and lessened frustration in the absence of repeated snags.
(f) to provide a chuck key that, when tethered to a drill""s power cord, resists the tendency to travel down the cord away from the operator;
(g) to provide a chuck key that, when tethered to a drill""s power cord, resists premature wear and failure of the tether;
(h) to provide a chuck key that can be securely gripped in the palm of the hand, resulting in increased comfort and greater manipulative leverage when actuating the jaws of a chuck;
(i) to provide a chuck key that can be readily gripped and manipulated even when the operators fingers are cold, gloved, sore, tired, or weak;
(j) to provide a chuck key that, when tethered to a drill""s power cord, will naturally come to rest in the palm of the hand while threading either end of the power cord through the hand;
(k) to provide a chuck key that allows for effective chuck operation by insertion of the key into just one of a series of chuck sockets;
(l) to provide a chuck key that allows for a convenient and rapid tightening and loosening of a chuck;
(m) to provide a chuck key that, when untethered from a drill""s power cord, can be visibly and securely stored upright in a narrow pocket of a conventional tool pouch; and
(n) to provide a chuck key that, when in use, tends to keep the operator""s fingers away from the meshing gears of the key and the chuck.
Further objects and advantages are to provide a chuck key that will reduce the threat of the financial burden associated with snag-related injury or property damage, and to reduce the anxiety that can be experienced in anticipation of these occurrences. Still further objects and advantages will become apparent from a consideration of the ensuing description and drawings.